bio question

[Dentexus]

What will happen to functioning acetylcholines at the end of their neural-signal transmission?



A. They will remain binding to receptors on the postsynaptic membrane.
B. They will diffuse through the postsynaptic membrane and are ready to be reused.
C. They will be absorbed by axon bearing the presynaptic membrane and are ready to be reused.
D. They will accumulate at the synaptic cleft for a prolonged period of time.
E. They will immediately be broken down by acetylcholinesterases at the synaptic cleft.


The anwer is E.
Why is C incorrect????

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[whiskeysour]

What will happen to functioning acetylcholines at the end of their neural-signal transmission?



A. They will remain binding to receptors on the postsynaptic membrane.
B. They will diffuse through the postsynaptic membrane and are ready to be reused.
C. They will be absorbed by axon bearing the presynaptic membrane and are ready to be reused.
D. They will accumulate at the synaptic cleft for a prolonged period of time.
E. They will immediately be broken down by acetylcholinesterases at the synaptic cleft.


The anwer is E.
Why is C incorrect????

b/c acetylcholine is not reused.

WS

 

[aranjuez]

Whiskey's right. ACh is degraded in the synapse by acetylcholinesterase, if I remember correctly. Only a part of the original molecule is then returned into the presynaptic neuron.

aranjuez

 

[tom_servo_dds]

Whiskey's right. ACh is degraded in the synapse by acetylcholinesterase, if I remember correctly. Only a portion of it is then returned into the presynaptic neuron.

aranjuez

That and it's pretty ubiquitous...

 

[Dentexus]

b/c acetylcholine is not reused.

WS

Oh. Thanks. I'm confused it with 5HT.

 

[djeffreyt]

What will happen to functioning acetylcholines at the end of their neural-signal transmission?



A. They will remain binding to receptors on the postsynaptic membrane.
B. They will diffuse through the postsynaptic membrane and are ready to be reused.
C. They will be absorbed by axon bearing the presynaptic membrane and are ready to be reused.
D. They will accumulate at the synaptic cleft for a prolonged period of time.
E. They will immediately be broken down by acetylcholinesterases at the synaptic cleft.


The anwer is E.
Why is C incorrect????

Just a correction of an earlier post. Althoug most Ach is broken down by acetylcholinesterases, some is reabsorbed by endocytosis and reused. However, "C" is wrong because it is reabsorbed at the synapse, by the membrance near the terminal end...it is not absorbed at the axon as it says in "C".